September 28, 2002, is one of the most significant dates in the history of American sports. You won’t find it in the record books.

That morning, on a stainless steel autopsy table inside the Allegheny County coroner’s office in Pittsburgh, Pennsylvania, lay the body of Mike Webster, the legendary center of the Pittsburgh Steelers. He had been stripped to his blue jeans, and his stomach had been injected with embalming fluid. Even in death, Webster looked formidable, with a muscular thickness from head to foot, a body that seemed designed to absorb and mete out punishment. But on closer inspection, it was a body that showed horrific signs of wear. Late in Webster’s life, his personal physician had noticed that the skin on his forehead had become “fixed to his scalp,” a shelf of scar tissue built up over 17 years of pro football. Odd bulges protruded from his back, varicose veins spidered down his legs, and deep cracks ran along the bottoms of his feet. His fingers were thick and crooked like splayed branches. Webster’s ex-wife, peering into his casket, had noticed that his fingers remained curled so that “it looked like he was still holding a football.” Webster was 50 years old when he died, but a lot of people thought he looked 70.

Five years earlier, when Webster was inducted into the Hall of Fame, his old quarterback, Terry Bradshaw, introduced him as “the best center that’s ever played the game, the best to ever put his hands down on a football.” Bradshaw, bald except for a fringe of blond hair, looking like a TV evangelist in his gold Hall of Fame sport coat, gazed up to the gray skies and cried: “One more time, let me put my hands under Mike Webster’s butt!” Webster, looking sheepish and befuddled, bent over in his khakis and hiked the ball to Bradshaw as the crowd roared. That was in 1997. Webster was already a very sick man. How sick, only a few people knew. Steelers fans had heard some of the stories: that Webster was broke and jobless and living in his truck, that his body was falling apart, that he was seeing a psychiatrist. The reality was far worse: Webster, a kind, thoughtful man during his playing days—many imagined he would go on to a successful career in coaching or perhaps broadcasting, like Bradshaw—had been transformed into a completely different person.

Webster had accumulated an arsenal of weapons that included a Sig Sauer P226 semiautomatic pistol, an AR-15 semiautomatic assault rifle, and a .357 Magnum revolver. He talked frequently about killing NFL officials, including Steelers executives and members of the league’s disability board, whom he blamed for his financial troubles. Webster had become addicted to Ritalin, a stimulant normally prescribed to children with attention-deficit disorder, finding that it was the only thing that got him through the day.

Webster, more than anyone, knew how sick he was, and he believed his illness was connected to the game to which he had given his life. Webster once went six seasons without missing a single offensive play; later, when asked by a doctor if he had ever been involved in a car crash, he replied: “Oh, probably about 25,000 times or so.” He read constantly, even during the worst of his illness, and he would pore over literature on head trauma and brain disease, putting exclamation points in the margins and circling terms that he thought applied to him, such as “ice pick headache” and “disinhibition” and “dysfluency.” He wrapped duct tape around his crooked fingers so that he could grasp a pen to write thousands of letters—some ranting and paranoid, some desperate, some incomprehensible—on any scrap of paper he could find

As Webster lay dead inside the coroner’s office that September morning, a silver Mercedes-Benz turned into the back parking lot. A small, dapper forensic pathologist named Bennet Omalu climbed out. It was a mild fall day in Pittsburgh, not yet cold, the start of another football season. Outside the building, TV trucks and reporters had gathered with the news that “Iron Mike” Webster, the indestructible force of four Super Bowl champions, the center of gravity of the Steeler dynasty—“our strength,” Bradshaw had called him—was inside on a slab.

Omalu was on call to perform autopsies that Saturday because he was the most junior pathologist in the office. He had been out clubbing the night before.

“What’s going on?” he asked his colleagues.

“It’s Mike Webster. His body is in there,” one of them whispered.

“Who is Mike Webster?” asked Omalu.

***

Omalu’s specialty was the science of death.

A deeply spiritual man, he believed, in fact, that he could talk to the dead. Before dissecting his subjects—murder victims, people who had died of unknown or suspicious causes—he carried on internal conversations with the people laid out before him, imploring the dead to help him figure out what had caused their demise.

Now he talked to Webster.

“Mike, you need to help me. I know there’s something wrong, but you need to help me tell the world what happened to you.”

Omalu used a scalpel to make a Y-shaped incision along the length of Webster’s torso. He peeled back Webster’s abdomen, which was thick and taut from the embalming fluid. He removed Webster’s rib cage with a small oscillating saw. He inspected the internal organs in situ and then removed them one by one. He weighed the organs—the liver, the pancreas, the heart—on a scale and then sliced them into pieces on a plastic cutting board before placing them in jars.

The assistant then propped up the back of Webster’s head on a rubber tee. She made incisions across the scalp and over the ears. She pushed the rough skin of Webster’s forehead over his eyes and pulled back his scalp to reveal the top of his head. To see the skull exposed is to understand the preciousness of its contents, the brain’s utter indispensability to who we are. The brain sits inside a quarter-inch-thick vault of bony plates, in a bath of cerebrospinal fluid. It is not easy to remove. The autopsy suite filled with the high-pitched whine of the circular saw as bone dust rose from Webster’s head.

For all the punishment Webster’s body had absorbed, his brain looked normal. It had no visible bruises or aneurysms within its soft gray folds. In its natural state, the brain is almost gelatinous; to examine it further would require soaking it for weeks in a tub of formaldehyde and water, a process known as fixing. The process stiffens the brain until it can be sliced like pound cake and then shaved into slivers to be viewed under a microscope.

But that wouldn’t be necessary here. The official cause of Webster’s death was “acute myocardial infarction”—a heart attack. The assistant began to gather Webster’s brain with his other organs, to be placed back inside his body.

Omalu paused. The death certificate had noted somewhat mysteriously that Webster suffered from “depression secondary to postconcussion syndrome.” Omalu thought about the reports he had seen on television that morning about Webster’s erratic behavior. He thought about a previous patient, a battered woman whose autopsy had shown signs of brain disease. “It was a decision that you just make in the spur of the moment,” he later would say.

“Fix the brain,” he ordered.

The assistant balked. Webster’s brain was normal, wasn’t it? He had died of a heart attack.